Many digital systems, for example, camera-based systems in automotive applications, display information to a user. Some or all of this information can be critical information that is considered important to be provided to the user. Examples of critical information can include images from cameras on a motor vehicle, and images generated to indicate vehicle speed, and other statuses. System requirements, for example safety requirements, may require that some action is to be taken by the display system should the critical information fail to be displayed.
Various techniques are known in the art for detecting a failure to display critical information. For example, a graphics source can compute a first hash value for an image to be displayed and a display controller can compute a second hash value for the image sent to the display. If the two hash values are the same, a system can have high confidence that the image provided by the graphics source is the same image that the display controller outputs. However, this type of system, based on characteristics of the image data alone, is unable to determine if the display actually succeeds in physically showing the image. For example, should a cable carrying image data from a display controller to a display fail, the display controller may provide the correct image data but the display will ultimately fail to receive the data and display it.
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